This invention relates to a driving system for an electro chromic display (refered to as EC hereinafter) colored and erased reversibly by electric energy, and particularly a driving system which refreshes the memory in the case where the display is executed, by using a memory function which keeps the coloring state for several hours of several days even after the cutting of a coloring voltage of EC.
Conventionally, the liquid crystal and the luminous diode are put to practical use in many fields as the display element for the small-sized digital display.
But they were not always satisfactory elements for the display of small-sized machinery such as watches, since the liquid crystal is indistinct under dim light while having a merit of low-electric consumption. On the contrary, the luminous diode has a high-electric consumption and is indistinct under bright light, while having a merit of clearness under dim light.
For that reason, EC which needs lower electric consumption than the luminous diode and provides a better display effect than the liquid cristal, has being studied energetically. The features of this EC are as follows:
(1) A visual field is remarkably wide.
(2) The life is determined by the times of the coloring-erasing cycles.
(3) The energy consumption is from several to several ten times mc/cm.sup.2, and is increased in proportion to the cycle times.
(4) It has a memory function which keeps the coloration state for several hours of several days after the cutting of the coloring voltage.